JP2020194088A - Electrophotographic photoreceptor, method for manufacturing electrophotographic photoreceptor, and image forming apparatus - Google Patents

Abstract

To provide an electrophotographic photoreceptor that prevents the occurrence of image deletion even after a long-term use.SOLUTION: An electrophotographic photoreceptor has a photoreceptor film including at least a photoconductive layer and a surface layer formed on a cylindrical conductive substrate. When the surface potential of the electrophotographic photoreceptor when a certain electric charge is given to the electrophotographic photoreceptor is regarded as a charging ability, in the axial direction of the electrophotographic photoreceptor at a portion where the photoreceptor film is formed, the arithmetic average roughness of an outer surface of the electrophotographic photoreceptor in an area with a high charging ability is larger than the arithmetic average roughness of the outer surface of the electrophotographic photoreceptor in an area with a low charging ability.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrophotographic photosensitive member, a method for producing an electrophotographic photosensitive member, and an image forming apparatus.

The shift to digitization and colorization of electrophotographic image forming devices is progressing, and the quality of output images is improved (high resolution, high definition, no density unevenness, image defects (white spots). There is an increasing demand for (such as no black spots).

An example of high resolution, which is a factor for improving image quality, is to reduce image flow generated by repeated image formation. When an image flow occurs, the reproducibility of fine lines and the like deteriorates, so that it is easy for the human eye to discriminate, and therefore, the demand for reducing the image flow is extremely high.

Although there are various causes of image flow, discharge products are formed by oxidizing the surface layer on the surface of the electrophotographic photosensitive member due to ozone generated in the electrophotographic forming apparatus and the applied current voltage. It is known that a decrease in surface resistance is a cause of occurrence.

Therefore, by pressing a cleaning means such as a cleaning blade or a cleaning roller against the surface of the photoconductor, waste toner on the surface of the photoconductor is removed, and at the same time, the surface of the photoconductor is polished by the cleaning means to produce a discharge product on the surface. Is reduced or eliminated to suppress the occurrence of image flow.

On the other hand, if the efficiency of removing the discharge products on the surface is improved by increasing the pressing pressure of the cleaning means, the frictional resistance between the surface of the photoconductor and the cleaning means increases.

As a result, the surface friction becomes large, and the surface of the photoconductor and the blade may be significantly worn. Further, the rotational torque of the photoconductor drum increases, and the load on the cleaning means increases, for example, the cleaning blade is turned over, the toner external additive slips through, and the charging roller in contact with the photoconductor drum is contaminated. In some cases, charging defects caused by the above may occur.

Therefore, as shown in Patent Document 1, a method of roughening the surface of the photoconductor drum in order to reduce the contact area between the photoconductor drum and the cleaning blade or toner has been proposed.

With these technologies, the surface of the photoconductor is polished to suppress the occurrence of image flow, and the frictional resistance between the surface of the photoconductor and the cleaning means is reduced to wear and clean the surface of the photoconductor and the blade. It is possible to suppress the occurrence of defects.

JP-A-11-143099

However, in recent years, for example, the networking of offices has progressed, and there have been cases where a large amount of digitized information is output. Further, electrophotographic image forming apparatus has come to be used in the printing field as well, and as described above, high image quality is required, and at the same time, high stability for stable and repetitive image formation is also required.

The above-mentioned technique has made it possible to form an image with some stability. However, since there are cases where image flow occurs when used for a long period of time, there is still room for improvement.

The present invention has been proposed in view of the above, and provides an electrophotographic photosensitive member that suppresses wear on the surface and blade of the photoconductor and the occurrence of cleaning defects, and at the same time suppresses the occurrence of image flow even after long-term use. To provide. Another object of the present invention is to provide an image forming apparatus having higher image quality and higher stability than the conventional one by using the electrophotographic photosensitive member of the present invention.

That is, in order to achieve the above-mentioned object, the present invention is an electrophotographic photosensitive member in which a photoconductor film containing at least a photoconducting layer and a surface layer is formed on a cylindrical conductive substrate. When the surface potential of the electrophotographic photosensitive member when a constant charge is applied to the photoconductor is defined as the charging ability, the charging ability of the electrophotographic photosensitive member in the axial direction of the portion where the photoconductor film is formed. It is characterized in that the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in a high region is larger than that in the region having low chargeability.

Further, in order to achieve the above-mentioned object, the image forming apparatus according to the present invention uses the electrophotographic photosensitive member, is placed in contact with or close to the electrophotographic photosensitive member, and applies a voltage to the electrophotographic photosensitive member. It is characterized by including a charging member for charging.

According to the present invention, it is possible to provide an electrophotographic photosensitive member that suppresses the occurrence of image flow even when used for a long period of time. Further, by using the electrophotographic photosensitive member of the present invention, it is possible to provide an image forming apparatus having higher image quality and higher stability than before.

It is a schematic block diagram which shows the structure of the electrophotographic photosensitive member of this invention. (A) is a figure which shows an example of an electrophotographic photosensitive member. FIG. (B) is a diagram showing an example of the axial distribution of the chargeability of the electrophotographic photosensitive member. FIG. (C) is a diagram showing an example of the axial distribution of the arithmetic mean roughness of the electrophotographic photosensitive member. It is a schematic block diagram which shows an example of the structure of the electrophotographic photosensitive member of this invention. It is a schematic block diagram which shows an example of the structure of another electrophotographic photosensitive member of this invention. It is a schematic vertical sectional view which shows an example of the deposition film forming apparatus of an amorphous silicon photoconductor. It is a schematic diagram which shows an example of the electrophotographic apparatus of this invention. It is a schematic diagram which shows an example of another electrophotographic apparatus of this invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
(Electrophotophotoreceptor)
FIG. 1 is a schematic configuration diagram for explaining the electrophotographic photosensitive member of the present invention. FIG. 1A shows a schematic cross-sectional view of the electrophotographic photosensitive member of the present invention. Here, in the electrophotographic photosensitive member 100, a photosensitive member film 110 composed of, for example, a lower charge injection blocking layer, a photoconducting layer, and a surface layer is laminated on a cylindrical conductive substrate 101. The electrophotographic photosensitive member 100 has an outer surface 111. The electrophotographic photosensitive member 100 is divided into two equal parts at the center, and the left side in the drawing is divided into a first region and the right side is divided into a second region.

FIG. 1B is a graph showing the axial distribution of the chargeability of the electrophotographic photosensitive member 100 of the present invention. The horizontal axis indicates the position of the electrophotographic photosensitive member 100 in the axial direction, and the vertical axis indicates the charging ability. The solid line in the figure is a graph showing the charging ability at each axial position.

In the figure, Va indicates the surface potential of the region having high chargeability in the axial direction, and Vb indicates the surface potential of the region having low chargeability. Further, V1 and V2 in the figure are the respective regions when the electrophotographic photosensitive member 100 is divided into two equal parts at the center, and the left side thereof is divided into the first region and the right side thereof is divided into the second region. It is an average value, and the average value of the first region is indicated by V1 and the average value of the second region is indicated by V2.

The charging ability in the present invention indicates the surface potential of the electrophotographic photosensitive member 100 when a constant charge is applied to the surface of the electrophotographic photosensitive member 100.

Next, FIG. 1 (FIG. 1) shows a state in which the surface roughness of the outer surface 111 of the electrophotographic photosensitive member 100 is controlled based on the axial distribution of the chargeability shown in FIG. 1 (b) of the electrophotographic photosensitive member 100. Shown in c).

FIG. 1C is a graph showing the axial distribution of the arithmetic mean roughness of the electrophotographic photosensitive member 100 of the present invention. The horizontal axis indicates the position of the electrophotographic photosensitive member 100 in the axial direction, and the vertical axis indicates the arithmetic mean roughness.

The solid line in the figure is a graph showing the arithmetic mean roughness at each axis position. In the figure, Ra indicates the arithmetic mean roughness of the portion corresponding to the surface potential Va of the region having high chargeability in the above-mentioned axial direction, and Rab corresponds to the surface potential Vb of the region having low chargeability in the above-mentioned axial direction. It shows the arithmetic mean roughness of the part to be used. Further, Ra1 and Ra2 in the figure are obtained in each region when the electrophotographic photosensitive member 100 is divided into two equal parts at the center, the left side thereof is defined as the first region, and the right side thereof is divided into the second region. It is the average value of the arithmetic mean roughness, and the average value of the first region is indicated by Ra1 and the average value of the second region is indicated by Ra2.

The outer surface 111 of the electrophotographic photosensitive member 100 has a region with high chargeability (Va) with respect to a region with low chargeability (position of Vb) based on the axial distribution of chargeability shown in FIG. 1 (b). The arithmetic mean roughness of (position) is increased (Raa> Rab).
The arithmetic mean roughness in the present invention is based on the surface roughness defined in JIS B 0601.

The present inventors consider the reason why the occurrence of image flow can be suppressed even after long-term use by the above configuration as follows.

As shown in FIG. 1, when an image is output by an electrophotographic apparatus using an electrophotographic photosensitive member 100 having axial unevenness in chargeability, electrophotographic photosensitive is used in order to reduce unevenness in the density of the image in the axial direction. It is common practice to reduce the unevenness of the surface potential of the body 100.

For example, when a corotron charging method using a corona charger is used as a means for charging the electrophotographic photosensitive member 100, the distance between the charging wire and the surface of the electrophotographic photosensitive member 100 is changed at both ends in the charger. Therefore, adjustments are made so as to reduce the axial unevenness of the surface potential of the electrophotographic photosensitive member 100 at the time of image formation.

Further, when the contact charging method is used as a means for charging the electrophotographic photosensitive member 100, not only a direct current (DC) voltage is applied to the charging member, but an alternating current (AC) voltage is superimposed. By repeating charging and static elimination, adjustment is performed so as to reduce axial unevenness of the surface potential of the electrophotographic photosensitive member 100 at the time of image formation.

In either case, the surface potential of the electrophotographic photosensitive member 100 is adjusted in the axially uniform direction, and therefore, the amount of charge applied to the surface of the electrophotographic photosensitive member 100 is non-uniform in the axial direction. Will be. For example, in order to bring the potential of the surface of the portion having a low chargeability closer to the portion having a high chargeability, it is necessary to increase the amount of charge on the surface as compared with the portion having a high chargeability. Therefore, the current flowing from the charging means toward the surface of the electrophotographic photosensitive member 100 increases.

As a result, the amount of ozone generated in the region with low chargeability increases as compared with the region with high chargeability.

As described above, when the charging ability of the electrophotographic photosensitive member 100 is uneven, the electrophotographic photosensitive member 100 is used to homogenize the surface potential of the electrophotographic photosensitive member 100 at the time of image formation for the purpose of image uniformity. Axial unevenness occurs in the current flowing through 100 and the amount of ozone generated. As a result, axial unevenness occurs in the discharge products on the surface of the electrophotographic photosensitive member 100.

That is, in the region with low chargeability, image formation is continuously performed in a situation where the discharge products on the surface of the electrophotographic photosensitive member 100 are relatively increased as compared with the region with high chargeability. Become.

In general, it is known that the discharge product reduces the surface resistance by adsorbing water or the like. Therefore, in the region where there are many discharge products, the decrease in resistance becomes large, and as a result, the current flowing through the electrophotographic photosensitive member 100 increases, which causes a phenomenon that the discharge products increase.

That is, when the discharge product becomes uneven, when used for a long period of time, the discharge product increases further in the region where the discharge product is abundant, so that the unevenness of the discharge product increases.

As a result, it is presumed that the removal of the discharge product by the cleaning means is insufficient, and image flow may occur.

In the present invention, the arithmetic mean roughness of the region with low chargeability is made smaller than the arithmetic mean roughness of the region with high chargeability. As a result, the coefficient of friction with the cleaning means is higher in the region having a low charging capacity than in the region having a high charging capacity, so that the removal efficiency of the discharge product is improved as compared with the region having a high charging capacity.

As a result, the unevenness of the discharge product on the surface of the electrophotographic photosensitive member 100 is significantly reduced, and the increase in the unevenness of the discharge product caused by the unevenness of the discharge product is suppressed. Therefore, it is presumed that the occurrence of image flow is suppressed even after long-term use.

In the present invention, when the arithmetic average roughness Ra of the outer surface 111 of the electrophotographic photosensitive member 100 is 0.04 μm or more and 0.2 μm or less, wear of the blade and occurrence of cleaning defects are suppressed, and at the same time, it is used for a long period of time. Even so, it is preferable to suppress the occurrence of image flow.
If the arithmetic mean roughness Ra is smaller than 0.04 μm, the coefficient of dynamic friction between the photoconductor drum and the cleaning means increases, so that the durability of the cleaning means may decrease. Further, when a cleaning blade is used as the cleaning means, the blade may be turned over and a cleaning defect may occur.
If the arithmetic mean roughness Ra is larger than 0.2 μm, the contact area between the photoconductor drum and the cleaning means decreases, so that the discharge products on the surface of the electrophotographic photosensitive member 100 cannot be efficiently removed, and during use. Image flow may occur.

As shown in FIG. 1 (b), the shape of the chargeability in the axial direction of the electrophotographic photosensitive member 100 has some inflection points, but changes generally gently over the entire axial direction.

For example, as will be described later, in the amorphous silicon electrophotographic photosensitive member and the organic electrophotographic photosensitive member, the change in the chargeability in the axial direction changes gently as shown in FIG. 1B due to the nature of the manufacturing method. Is common, and does not change significantly locally.

Therefore, as shown in FIG. 1B, the electrophotographic photosensitive member is divided into two regions (first region and second region) in the axial direction, and the first region and the second region are divided. The chargeability of the electrophotographic photosensitive member 100 can be averaged in each range of the region, and the magnitude relationship of the absolute value of the chargeability of the electrophotographic photosensitive member 100 can be determined by the absolute value of the average value of the chargeability.

The outer surface 111 of the electrophotographic photosensitive member 100 has a first region having a high chargeability with respect to a second region having a low chargeability, based on the axial distribution of the chargeability shown in FIG. 1 (b). The average value of the arithmetic mean roughness of is increased (Ra1> Ra2).

In the present invention, as described above, the average value of the chargeability of the first region is V1, the average value of the chargeability of the second region is V2, the average value of the arithmetic mean roughness of the first region is Ra1, and so on. When the average value of the arithmetic mean roughness of the region 2 is Ra2, it is preferable to satisfy the following equations (1) and (2).

The average value (V1 + V2) / 2 of the chargeability of the entire electrophotographic photosensitive member 100 (first region + second region) of the difference in chargeability between the first region and the second region | V1-V2 | When the ratio to 10% is larger than 10%, the unevenness of the charging ability in the axial direction becomes large, and the uniformity of the image may become insufficient.

Further, the magnitude ΔRa of the axial unevenness of the arithmetic mean roughness is set to the difference between the arithmetic mean roughness of the first region and the second region | Ra1-Ra2 |, and the entire electrophotographic photosensitive member 100 (first). Area + 2nd area) is the ratio of the arithmetic mean roughness to the average value (V1 + V2) / 2. The magnitude ΔV of the axial unevenness of the chargeability is the difference in chargeability between the first region and the second region | V1-V2 |, and the entire electrophotographic photosensitive member 100 (first region + second region). The ratio of the chargeability of the region) to the average value (V1 + V2) / 2.

Here, if ΔRa is smaller than ΔV by more than 5%, that is, if the axial difference in the arithmetic mean roughness is insufficient, the unevenness of the discharge product, which is the gist of the present invention, is not sufficiently reduced. In some cases, it is not preferable. Further, when ΔRa is larger than ΔV by more than 5%, that is, when the difference in the arithmetic mean roughness in the axial direction is too large, chattering of the cleaning blade may occur, which is not preferable.

(Manufacturing method of photoconductor)
Next, the method for producing the electrophotographic photosensitive member 100 of the present invention will be described with reference to the drawings. 2 and 3 are schematic views showing a part of a cross section of the electrophotographic photosensitive member 100 shown in FIG.

In FIG. 2, the electrophotographic photosensitive member 200 shows an amorphous silicon photosensitive member as an example. A photoconductor film 210 composed of a lower charge injection blocking layer 202, a photoconducting layer 203, and a surface layer 204 is laminated on a cylindrical conductive substrate 201. The electrophotographic photosensitive member 200 has an outer surface 211. The conductive substrate 201 has an outer surface 212.

In FIG. 3, the electrophotographic photosensitive member 300 shows an organic photosensitive member as an example. A photoconductor film 310 composed of an undercoat layer 302, a charge generation layer 303, a charge transport layer 304, and a protective layer 305 is laminated on a cylindrical conductive substrate 301. The electrophotographic photosensitive member 300 has an outer surface 311. The conductive substrate 301 has an outer surface 312.

In FIG. 2, the outer surface 212 of the conductive substrate 201 is roughened, and as a result, the outer surface 211 of the photoconductor film 210 deposited on the conductive substrate 201 is roughened.

The roughening method is not particularly limited, and the outer surface 212 of the conductive substrate 201 may be roughened by, for example, wet blasting, dry lasting, wet etching, dry etching, polishing, or cutting.

Then, the roughening may be performed differently by changing the roughening conditions in the region having a high charging ability and the region having a low charging ability, and also in the first region and the second region.

Further, between the region with high chargeability and the region with low chargeability, and at the boundary between the first region and the second region, the treatment conditions may be changed sharply at the boundary, and the treatment is gradually performed within a certain range. The conditions may be changed.

Next, the conductive substrate 201 whose outer surface 212 is roughened in this way is put into a deposition film forming apparatus described later, and the photoconductor film 210 is deposited on the conductive substrate 201. At this time, it is necessary to input the positional relationship between the side having the large arithmetic mean roughness and the side having the small arithmetic mean roughness of the conductive substrate 201 so as to have a predetermined positional relationship.

Specifically, the axial distribution of the chargeability of the electrophotographic photosensitive member 200 created by the deposit film forming apparatus in advance is measured. Then, a portion having a high charging ability and a portion having a low charging ability are determined. As a result, the positional relationship between the highly chargeable portion and the sedimentary film forming apparatus is determined. After that, the sedimentary film so that the side of the outer surface 211 of the electrophotographic photosensitive member 200 created as described above, which has a large arithmetic mean roughness, is the same as the portion having a high chargeability due to the positional relationship of the deposit film forming apparatus. Put into the forming device.

This will be described using the deposit film forming apparatus 400 shown in FIG. FIG. 4 is a diagram schematically showing an example of a deposition film forming apparatus 400 for an electrophotographic photosensitive member by an RF plasma CVD method using a high frequency power source for producing an amorphous silicon photosensitive member 200. This device is roughly classified into a deposition device 480 having a reaction vessel 401, a raw material gas supply device 490, and an exhaust device (not shown) for reducing the pressure inside the reaction vessel 401.

In the reaction vessel 401 in the deposition apparatus 480, a conductive substrate 101 connected to the ground, a heater 402 for heating the substrate, and a raw material gas introduction pipe 403 are installed. Further, a high frequency power supply 406 is connected to the cathode electrode 404 via a high frequency matching box 405.

The raw material gas supply device 490 is provided with a raw material gas cylinder (not shown) such as SiH ₄ , H ₂ , CH ₄ , NO, B ₂ H ₆ . The gas cylinder filled with each raw material gas is connected to the raw material gas introduction pipe 403 in the reaction vessel 401 via an auxiliary valve 407.

Next, a method of forming a sedimentary film using this device will be described. As described above, the conductive substrate 201 having the outer surface 212 roughened in advance has a region having a large arithmetic mean roughness of the outer surface 212 as a region having a high chargeability due to the positional relationship in the deposition film forming apparatus 400. It is installed in the reaction vessel 401 via the cradle 408 so as to be the same.

For example, when an amorphous silicon photoconductor is produced using the deposition film forming apparatus 400 of FIG. 4, a region having a low charging ability is formed on the pedestal 408 side, and a region having a high charging ability is formed on the side opposite to the pedestal 408. It is formed. Therefore, it is installed in the reaction vessel 401 so that the region of the outer surface 212 having a large arithmetic mean roughness on the conductive substrate 201 is on the opposite side to the cradle 408.

Next, the exhaust device (not shown) is operated to exhaust the inside of the reaction vessel 401. While observing the display of the vacuum gauge 409, power is supplied to the substrate heating heater 402 in the region where the pressure in the reaction vessel 401 becomes a predetermined pressure of, for example, 1 Pa or less, and the conductive substrate 201 is, for example, from 50 ° C. to 350 ° C. Heat to the desired temperature of ° C. At this time, an inert gas such as Ar or He can be supplied to the reaction vessel 401 from the raw material gas supply device 490 to perform heating in the inert gas atmosphere.

Next, the gas used for forming the sedimentary film is supplied to the reaction vessel 401 from the raw material gas supply device 490. That is, the flow rate is set by using a mass flow controller (not shown) as needed. In the region where the flow rate of each mass flow controller (not shown) is stable, the main valve 410 is operated while observing the display of the vacuum gauge 409 to adjust the pressure in the reaction vessel 401 to a desired pressure. At the same time as applying high frequency power from the high frequency power supply 406 in the region where the desired pressure is obtained, the high frequency matching box 405 is operated to generate plasma discharge in the reaction vessel 401. After that, the high frequency power is promptly adjusted to a desired power to form a sedimentary film.

At the region where the formation of the predetermined deposit film is completed, the application of the high frequency power 406 is stopped, the auxiliary valve 407 is closed, and the supply of the raw material gas is finished. At the same time, the main valve 410 is fully opened, and the inside of the reaction vessel 401 is exhausted to a pressure of 1 Pa or less.

This completes the formation of the deposit film, but when forming a plurality of deposit films, the above procedure may be repeated again to form each layer. It is also possible to form the junction region by changing the flow rate of the raw material gas, the pressure, and the like to the conditions for forming the photoconductor film in a certain time.

After all the deposition film formation is completed, the main valve 410 is closed, an inert gas is introduced into the reaction vessel 401, the pressure is returned to atmospheric pressure, and then the conductive substrate 101 is taken out.

Next, another manufacturing method will be described with reference to FIG.
First, the photoconductor film 310 is formed on the conductive substrate 301. Then, the axial distribution of the chargeability of the created electrophotographic photosensitive member 300 is measured. As a result, a region having a high chargeability or a first region having a high chargeability and a region having a low chargeability or a second region having a low chargeability are determined. As a result, the arithmetic mean roughness of the outer surface 311 of the electrophotographic photosensitive member 300 is roughened so that the first region having high chargeability is larger than the region having low chargeability. Similarly, the first region with high chargeability is roughened so as to be larger than the second region with low chargeability.

In this case, the method for roughening the outer surface 311 of the electrophotographic photosensitive member 300 is not particularly limited. For example, the electrophotographic photosensitive member 300 is brought into pressure contact with a mold having a drive last, polishing, or a fine uneven shape, and the fine uneven shape is transferred to the outer surface 311 to roughen the outer surface 311. Just do it.

Then, the roughening may be performed differently by changing the roughening conditions in the region having a high charging ability and the region having a low charging ability, and also in the first region and the second region.

Further, between the region with high chargeability and the region with low chargeability, and at the boundary between the first region and the second region, the treatment conditions may be changed sharply at the boundary, and the treatment is gradually performed within a certain range. The conditions may be changed. Further, the electrophotographic photosensitive member 100 may be prepared by combining the above methods.

This will be described with reference to FIG. First, the photoconductor film 210 is formed on the conductive substrate 201 whose outer surface 212 is roughened. At this time, the roughening is performed so that the arithmetic mean roughness is substantially equal over the entire conductive substrate 201. The axial distribution of the chargeability of the created electrophotographic photosensitive member 200 is measured. As a result, a region having a high chargeability and a region having a low chargeability are determined. As a result, the outer surface 211 of the electrophotographic photosensitive member 200 is roughened so that the arithmetic mean roughness of the region with high chargeability is larger than that of the region with low chargeability.

At this time, the roughening may be performed only in the region with high chargeability so that the arithmetic mean roughness of the region with high chargeability is larger than that in the region with low chargeability. Further, only the region with low chargeability may be performed so that the arithmetic mean roughness of the region with low chargeability is smaller than that in the region with high chargeability.

Further, the chargeability of the electrophotographic photosensitive member 100 may be measured every time the electrophotographic photosensitive member 100 is formed, but when the electrophotographic photosensitive member 100 is produced under the same conditions, the measurement is performed once. After that, the electrophotographic photosensitive member 100 may be roughened under the same conditions.

(Electrographer)
Next, the electrophotographic apparatus using the electrophotographic photosensitive member 100 of the present invention will be described with reference to the drawings.

FIG. 5 is a diagram showing an example of an electrophotographic apparatus 500 using the electrophotographic photosensitive member 100 of the present invention. The formation of the electrophotographic image by the electrophotographic apparatus 500 shown in FIG. 5 is performed as follows. In FIG. 5, the surface of the electrophotographic photosensitive member 100, which is rotationally driven in the direction of the arrow, is charged by the charging device 501. The charging potential on the surface of the electrophotographic photosensitive member 100 is adjusted by the value of the current flowing through the charging wire 502 in the charging device 501. At this time, the distance between the charging wire 502 and the surface of the electrophotographic photosensitive member 100 is adjusted in advance so that the charging potential on the surface of the electrophotographic photosensitive member 100 approaches uniformly.

Next, the surface of the electrophotographic photosensitive member 100 is irradiated with image exposure light 503 from an image exposure apparatus (not shown), and an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member 100. After that, the electrostatic latent image formed on the surface of the electrophotographic photosensitive member 100 is developed by the toner supplied from the developing device 504, and the toner image is formed on the surface of the electrophotographic photosensitive member 100. After that, the toner image formed on the surface of the electrophotographic photosensitive member 100 is transferred to the transfer material 506 by the transfer device 505. Next, the transfer material 506 is separated from the surface of the electrophotographic photosensitive member 100, and then the toner image transferred to the transfer material 506 is fixed to the transfer material 506 by a fixing device (not shown).

On the other hand, the toner remaining on the surface of the electrophotographic photosensitive member 100 without being transferred to the transfer material 506 is removed by the cleaning blade 508 in the cleaning device 507. After that, the surface of the electrophotographic photosensitive member 100 is irradiated with pre-exposure light 509 from a pre-exposure apparatus (not shown), and the surface of the electrophotographic photosensitive member 200 is statically eliminated. By repeating this series of processes, image formation (image output) is continuously performed.

Further, another electrophotographic apparatus using the electrophotographic photosensitive member 100 of the present invention will be described with reference to the drawings.

FIG. 6 is a diagram showing an example of an electrophotographic apparatus 600 using the electrophotographic photosensitive member 100 of the present invention. The electrophotographic image is formed by the electrophotographic apparatus 600 shown in FIG. 6 as follows. In FIG. 6, the surface of the electrophotographic photosensitive member 100, which is rotationally driven in the direction of the arrow, is charged by the charging roller 601.

The charging roller 601 is arranged parallel to the electrophotographic photosensitive member 100 and rotates in the direction opposite to that of the electrophotographic photosensitive member 100 (counterclockwise in the drawing) to come into contact with or approach the outer surface 111 of the electrophotographic photosensitive member 100. Be placed. Then, a voltage is applied by being connected to the power supply 610, and the surface of the electrophotographic photosensitive member 100 whose charge is eliminated by the pre-exposure light 609 by discharging from the charging roller 601 to the electrophotographic photosensitive member 100 has a predetermined polarity and potential. It is charged so as to become. The charging potential on the surface of the electrophotographic photosensitive member 100 is adjusted by the DC voltage and AC voltage applied to the charging roller 601.

Next, the surface of the electrophotographic photosensitive member 100 is irradiated with image exposure light 603 from an image exposure apparatus (not shown), and an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member 100. After that, the electrostatic latent image formed on the surface of the electrophotographic photosensitive member 100 is developed by the toner supplied from the developing device 604, and the toner image is formed on the surface of the electrophotographic photosensitive member 100. After that, the toner image formed on the surface of the electrophotographic photosensitive member 100 is transferred to the transfer material 606 by the transfer device 605. Next, the transfer material 606 is separated from the surface of the electrophotographic photosensitive member 100, and then the toner image transferred to the transfer material 606 is fixed to the transfer material 606 by a fixing device (not shown).

On the other hand, the toner remaining on the surface of the electrophotographic photosensitive member 100 without being transferred to the transfer material 606 is removed by the cleaning blade 608 in the cleaning device 607. After that, the surface of the electrophotographic photosensitive member 100 is irradiated with preexposure light 609, and the surface of the electrophotographic photosensitive member 100 is statically eliminated. By repeating this series of processes, image formation (image output) is continuously performed.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the following description, the same reference numerals will be used for the same parts as those shown in the above-described embodiment.

<Example 1>
As the cylindrical conductive substrate 201 shown in FIG. 2, an amorphous silicon electrophotographic photosensitive member 200 having a diameter of 84 mm, a length of 381 mm, and a wall thickness of 3 mm made of aluminum was prepared as follows.

The outer surface 212 of the conductive substrate 201 was subjected to mirror cutting and wet blasting, and at the end of each processing, the conductive substrate 201 was washed.

First, as a mirror cutting process, in order to prevent vibration of the cylindrical conductive base 201, a urethane rubber cylinder is inserted inside the conductive base 201 so as to be in close contact with the inside of the conductive base 201, and the inner circumference of the conductive base 201 is formed. Was sandwiched from the left and right by the tapered surface of the spindle yatoi and the tailstock yatoi and installed in the cutting device.

After that, the conductive substrate 201 is rotated at a high speed of 1000 to 8000 rpm, the feed pitch per rotation to the conductive substrate 201 is set to 0.05 to 0.3 mm, the depth of cut of the diamond bite for rough cutting, and finish cutting. The depth of cut of the diamond cutting tool for cutting was set, and the diamond cutting tool was pressed against the conductive substrate 201 so that the outer diameter of the conductive substrate 201 after cutting was set to a predetermined outer diameter. When the cutting was completed, the conductive substrate 201 was removed from the cutting device, moved to a washing machine, and degreased and washed.

Next, the conductive substrate 201 is installed in a wet blasting apparatus while holding both ends of the inner surface of the conductive substrate 201. After that, the conductive substrate 201 is rotated at 10 to 100 rpm, and a solution of a mixture of an abrasive made of alumina and water is applied to the surface of the conductive substrate 201 so that the concentration of the abrasive is 5 to 20 Vol% from the projection nozzle. Was mixed with and projected onto the outer surface 212 of the conductive substrate 201. The air pressure at the time of projection at this time was 0.10 to 0.30 MPa, and the moving speed of the projection nozzle was 10 to 0.1 mm / sec.
Then, with respect to the pressure of the air at the time of projection from the wet blasting start end of the conductive base 201 to the center of the conductive base 201, the air from the center to the end of the remaining conductive base 201 The pressure was reduced to change the arithmetic mean roughness of the outer surface 212 of the conductive substrate 201. When the processing was completed, the conductive substrate 201 was removed from the wet blasting apparatus, moved to a washing machine, and washed using pure water and ultrasonic waves.

After that, the conductive substrate 201 was installed in the reaction vessel 401 so that the above-mentioned wet blasting start end was on the opposite side to the cradle 408. Then, using the deposition film forming apparatus 400 as described above, as shown in FIG. 2 under the conditions shown in Table 1, the lower charge injection blocking layer 202 and the photoconductivity are placed on the cylindrical conductive substrate 201. An amorphous silicon photoconductor 200 was formed by forming a photoconductor film 210 composed of a layer 203 and a surface layer 204.

With respect to the produced amorphous silicon photoconductor 200, "chargeability", "film thickness of photoconductor film", "arithmetic mean roughness", "image flow", and "cleanability" were evaluated as follows.

"Charging ability"
The prepared electrophotographic photosensitive member was installed in a modified machine obtained by modifying Canon's iRC6800 to a negative charging method, and the charging ability of the photosensitive member was evaluated. The electrophotographic photosensitive member was charged under the conditions of a process speed of 265 mm / sec, a pre-exposure (LED having a wavelength of 660 nm) of 4 μJ / cm ^2, and a current value of the main charger of 1000 μA. At this time, the dark surface potential of the electrophotographic photosensitive member was measured with a surface electrometer (Model 555P-4 manufactured by TREK). The dark area surface potential is the average value in the circumferential direction, and the average value of the dark area surface potential is used as the charging ability. Regarding the axial direction of the electrophotographic photosensitive member, 7 points of ± 50 mm, ± 100 mm, and ± 150 mm were measured with the center as 0 mm. Then, in the axial direction, the region having the highest charging ability and the region having the lowest charging ability were extracted.

"Film thickness of photoconductor film"
In the present invention, the film thickness of the photoconductor film was measured using a film thickness meter (FISCHER SCOPE MMS manufactured by Fisher Instruments). The measurement positions are 7 points of ± 50 mm, ± 100 mm, and ± 150 mm with the center as 0 mm in the axial direction of the photoconductor, and 4 points in the circumferential direction at 90 degree intervals in the circumferential direction at each axial position described above. And said. There are a total of 28 measurement points. The film thickness of the photoconductor film at each axial position was taken as an average value in the circumferential direction. Then, in the axial direction, a region having a thick film thickness and a region having the thinnest film thickness were extracted.

"Arithmetic mean roughness"
In the present invention, the arithmetic mean roughness Ra was measured using a foam tracer SV-C4000S4 (Mitutoyo Co., Ltd.) based on JIS B0651: 2001. The shape of the stylus used was in accordance with JIS B0651: 2001. That is, the tip shape was a cone having a spherical tip, the tip radius was 2 μm, the taper angle of the cone was 60 °, and the measuring force was 0.75 mN.
In addition, the reference length, evaluation length, λs contour curve filter (filter that defines the boundary between the roughness component and the shorter wavelength component), and λc contour curve filter (define the boundary between the roughness component and the waviness component). The settings of the filter) were in accordance with JIS B0633: 2001 and JIS B0651: 2001.
The scanning speed was 0.1 mm / sec, and the measurement environment was an air temperature of 25 ° C. and a humidity of 65%. Other conditions not specifically described were all based on JIS B0601: 2001, JIS B0633: 2001, and JIS B0651: 2001. Further, all the measurement procedures by the specific foam tracer SV-C4000S4 were performed according to the instruction manual attached to the device.
The measurement positions of the photoconductor in the axial direction are 7 points of ± 50 mm, ± 100 mm, and ± 150 mm with the center as 0 mm, and the measurement positions in the circumferential direction are 4 at 90 degree intervals in the circumferential direction at each of the above-mentioned axial positions. It was a point. The total number of measurement points was 28. Then, the arithmetic mean roughness of each axis position was taken as the average value in the circumferential direction. Then, in the axial direction, the arithmetic mean roughness of the region having the highest chargeability and the arithmetic mean roughness of the region having the lowest chargeability were extracted.

"Image flow"
The evaluation of the image flow was performed using a modified machine obtained by modifying the Canon iRC6800 to a negative charging method. First, an electrophotographic photosensitive member was installed, and uneven charging in the axial direction was adjusted. The electrophotographic photosensitive member is charged under the condition that the current value of the main charger is 1000 μA, and at this time, the dark surface potential of the electrophotographic photosensitive member is measured by a surface electrometer (Model 555P-4 manufactured by TREK). Then, the distance between the charging wire in the main charger and the surface of the electrophotographic photosensitive member was adjusted so that the unevenness in the axial direction of the dark surface potential was reduced. Specifically, the distance between the charging wire located on the side with the lowest charging ability and the surface of the electrophotographic photosensitive member was brought closer. Then, the unevenness of the surface potential of the dark portion in the axial direction was adjusted to 15 V or less.

Next, at a resolution of 1200 dpi, using an area gradation dot screen with a linear density of 45 degrees 170 lpi (170 lines per inch), gradation data was created in which the entire gradation range was evenly distributed in 17 steps. At this time, the darkest gradation was set to 17 and the lightest gradation was set to 0, and numbers were assigned to each gradation to set the gradation step.
Then, using the above-mentioned gradation data, the text mode was used to output to A3 paper. At this time, if a high humidity flow occurs, the evaluation of the image flow is affected. Therefore, in an environment of a temperature of 22 ° C. and a relative humidity of 50%, the photoconductor heater is turned on and the surface of the photoconductor for electrophotographic is about 40. The output was performed under the condition of keeping the temperature at ° C.

Next, a durability test of 100,000 sheets was carried out. After the endurance, the above-mentioned gradation data is used to output A3 paper using the text mode, and among the obtained images, a reflection densitometer (manufactured by X-Rite Inc: 504 spectral density) is used for each gradation of 0 to 8 gradations. The image density was measured by the total). In the reflection density measurement, three images were output for each gradation, and the average value of those densities was used as the evaluation value. The coefficient of determination R2 value when the evaluation value thus obtained and the gradation step were linearly approximated was calculated. At this time, the evaluation criteria are as follows.
A ... R2 is 0.996 or more B ... R2 is 0.990 or more and less than 0.96 C ... R2 is less than 0.990

"Cleanability"
In the same manner as described above, after performing the durability test of 100,000 sheets, the entire halftone image is output on A3 paper, and the obtained image shows the presence or absence of cleaning failure depending on the presence or absence of streaks in the rotation direction of the electrophotographic photosensitive member. Was evaluated. If the streaks were visually recognized, it was considered that there was a cleaning failure. At this time, the evaluation criteria are as follows.
A: No cleaning failure B: Photoreceptor rotation direction streaks within 3 mm and 2 lines C: Photoreceptor rotation direction streaks within 3 mm width 2 or more One or more of 3 mm or more.
The results obtained are shown in Table 2.

<Comparative example 1>
In this comparative example, an electrophotographic photosensitive member was prepared in the same manner as in Example 1. However, in this comparative example, during the wet blasting process, the wet blasting process was performed without changing the air pressure from the wet blasting start end portion of the conductive substrate to the other end portion of the conductive substrate. That is, all were carried out in the same manner as in Example 1 except that the arithmetic mean roughness of the outer surface of the conductive substrate was not changed in the axial direction. Then, the same evaluation as in Example 1 was performed. The results obtained are shown in Table 2.

As is clear from Table 2, by making the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member in the region with high chargeability larger than that in the region with low chargeability, good cleanability even after long-term use. It was found that it is possible to suppress the occurrence of image flow by maintaining the above.

In Comparative Example 1, an image flow occurred in the vicinity of −150 mm at a position in the axial direction where the charging ability was low. At this time, it was confirmed that the area where the outer surface of the electrophotographic photosensitive member was confirmed-150 mm, had more discharge products on the surface than in other places.

Similarly, the region where the outer surface 211 of the electrophotographic photosensitive member 200 of the present invention of Example 1 was confirmed, and the discharge product could hardly be confirmed on the entire surface of the electrophotographic photosensitive member.

Further, the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member in the region where the film thickness of the photoconductor film is thick is made larger than that in the region where the film thickness of the photoconductor film is thin, so that it is good even if it is used for a long period of time. It is possible to provide an electrophotographic photosensitive member that maintains cleanability and suppresses the occurrence of image flow.

The capacitance of the photoconductor film is larger in the region where the film thickness is thin than in the region where the film thickness is thick. Therefore, when the same charge is applied, the surface potential of the region having a thin film thickness is lower than that of the region having a thick film thickness. Therefore, in order to obtain the same surface potential, it is necessary to increase the amount of electric charge applied. Therefore, the amount of discharge products is larger in the thin region than in the thick region. Therefore, the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in the region where the film thickness of the photoconductor film of the present invention is thick is made larger than the region where the film thickness of the photoconductor film is thin, so that it can be used for a long period of time. It is also possible to provide an electrophotographic photosensitive member that maintains good cleanability and suppresses the occurrence of image flow.

<Example 2>
In this example, an electrophotographic photosensitive member was prepared in the same manner as in Example 1. However, in this embodiment, during the wet blasting process, the pressure remaining from the center to the air pressure during projection from the wet blasting start end of the conductive substrate 201 to the center of the conductive substrate 201. The pressure of air to the end of the conductive substrate 201 was changed to change the arithmetic mean roughness of the outer surface 212 of the conductive substrate 201. Subsequently, the following evaluation was performed.

"Charging ability"
The measurement was carried out in the same manner as in Example 1. However, in this embodiment, when the portion where the photoconductor film 210 is formed is divided into two regions in the axial direction and the average value of the charging ability is calculated in each region, the 0 mm position is set. The three points in the axial direction of each of the excluded + side and-side regions were averaged and calculated. The side with a high average chargeability is the first region, the side with a low average chargeability is the second region, the average value of the chargeability in the first region is V1, and the average value of the chargeability in the second region is V2. And said. Further, the unevenness ΔV (%) of the charging ability was calculated from the following formula (3).

さらに、帯電能のムラΔＶ（％）と算術平均粗さのムラΔＲａ（％）との差を下記式（５）とし、算術平均粗さを算出した。
ΔＶ−ΔＲａ 式（５） "Arithmetic mean roughness"
The measurement was carried out in the same manner as in Example 1. However, in this embodiment, when the portion where the photoconductor film 210 is formed is divided into two regions in the axial direction and the average value of the arithmetic mean roughness is obtained in each region, it is 0 mm. A total of 12 points, 3 points in the axial direction and 4 points in the circumferential direction, were obtained by averaging each of the + side and-side regions excluding the positions. Then, the average value of the arithmetic mean roughness in the first region where the average value of the chargeability is high is Ra1, and the average value of the arithmetic mean roughness in the second region where the average value of the chargeability is low is defined as Ra1. It was set to Ra2. Further, the unevenness ΔRa (%) of the arithmetic mean roughness was calculated from the following formula (4).

Further, the difference between the unevenness ΔV (%) of the charging ability and the unevenness ΔRa (%) of the arithmetic mean roughness was set to the following formula (5), and the arithmetic mean roughness was calculated.
ΔV−ΔRa equation (5)

"Image flow and cleanability"
The same evaluation as in Example 1 was performed. The results obtained are shown in Table 3.

<Comparative example 2>
In this comparative example, an electrophotographic photosensitive member was prepared in the same manner as in Example 2. However, in this comparative example, during the wet blasting process, the wet blasting process was performed without changing the air pressure from the wet blasting start end portion of the conductive substrate 201 to the other end portion of the conductive substrate 201. .. That is, all were carried out in the same manner as in Example 2 except that the arithmetic mean roughness of the outer surface 212 of the conductive substrate 201 was not changed in the axial direction. Then, the same evaluation as in Example 2 was performed. The results obtained are shown in Table 3.

As is clear from Table 3, the electrophotographic photosensitive member in the portion where the photoconductor film is formed is divided into two regions in the axial direction, and the side having the higher average charging ability of the electrophotographic photosensitive member is divided into two regions. When the lower side of the first region is set as the second region, the average value of the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member in the first region is made larger than that of the second region to obtain a length. It is possible to provide an electrophotographic photosensitive member that maintains good cleanability even after being used for a period of time and suppresses the occurrence of image flow.
Further, it was found that it is more preferable to satisfy the following formula (6) and the following formula (7).

If the arithmetic mean roughness unevenness ΔRa (%) is smaller than 5% with respect to the arithmetic mean roughness ΔV (%), that is, if there is not much difference in the arithmetic mean roughness in the axial direction, in the region where the arithmetic mean roughness is low. There was a slight case of image flow.

The fact that there is not much difference in the arithmetic mean roughness in the axial direction means that the adhesion of discharge products is relatively large. It is not small enough for the high capacity area. Therefore, it is considered that the increase in uneven adhesion of the discharge product cannot be sufficiently suppressed.

On the other hand, when the unevenness ΔRa (%) of the arithmetic mean roughness is larger than 5% with respect to the unevenness ΔV (%) of the charging ability, that is, when the difference in the axial direction of the arithmetic mean roughness is large, cleaning is slight. There was a case of shortage. As a result of investigating the cause of the occurrence, it was found that chattering of the cleaning blade occurred in the region where the charging ability was small = the region where the arithmetic mean roughness was small.

It is considered that this was caused by a difference in frictional resistance between the cleaning blade and the surface of the photoconductor in the axial direction, and the dynamic frictional resistance increased in the smaller arithmetic mean roughness.

Therefore, by reducing the pressing pressure of the cleaning blade, the chattering of the cleaning blade could be eliminated, but the region with high charging ability = the region with large arithmetic mean roughness near the center of the electrophotographic photosensitive member, although it was a slight image. It turned out that a flow may occur. It is considered that this is because the pressing pressure of the cleaning blade is reduced, so that the discharge product may not be sufficiently removed.

Therefore, it is preferable to control the unevenness ΔRa (%) of the arithmetic mean roughness to ± 5 (%) with respect to the unevenness ΔV (%) of the charging ability.

<Example 3>
In this example, an electrophotographic photosensitive member was prepared in the same manner as in Example 1. Then, the Canon iRC6800 was modified from the corona charging method shown in FIG. 5 to a contact charging method in which the charging roller 601 contacts the electrophotographic photosensitive member and is negatively charged as shown in FIG. In order to charge the electrophotographic photosensitive member, a direct current (DC) voltage was applied to the charging roller 601, and an alternating current (AC) voltage was superimposed and the voltage was applied.
First, the electrophotographic photosensitive member 100 was installed, and the voltage applied to the charging roller was adjusted so that the average of one circumference of the dark surface potential at the center (0 mm) position of the electrophotographic photosensitive member 100 was 500 V. After that, the durability test of 100,000 sheets was carried out in the same manner as in Example 1, and the image flow and the cleanability were evaluated. As a result, no image flow occurred and the cleanability was good.

<Example 4>
As the cylindrical conductive substrate 301 shown in FIG. 3, a diameter of 30 mm, a length of 370 mm, and a wall thickness of 7.5 mm made of aluminum was used, and as shown in FIG. 3, on the cylindrical conductive substrate 301. An organic photoconductor 300 was formed by forming a photoconductor film 310 composed of an undercoat layer 302, a charge generation layer 303, a charge transport layer 304, and a protective layer 305. Each component of the organic photoconductor 300 was prepared as follows. "Parts" in the examples means "parts by mass".

"Underlay layer"
A solution consisting of the following components was dispersed in a ball mill for about 20 hours to prepare a paint.
-60 parts of powder consisting of barium sulfate particles having a tin oxide coating layer (trade name: Pastran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.)
・ 15 parts of titanium oxide (trade name: TITANIX JR, manufactured by TAYCA CORPORATION)
-Resol type phenolic resin 43 parts (trade name: Phenolite J-325, manufactured by Dainippon Ink and Chemicals Co., Ltd., solid content 70%)
・ 0.015 parts of silicone oil (trade name: SH28PA, manufactured by Toray Silicone Co., Ltd.)
-Silicone resin 3.6 parts (trade name: Tospearl 120, manufactured by Toshiba Silicone Co., Ltd.)
・ 50 parts of 2-methoxy-1-propanol ・ 50 parts of methanol The paint prepared in this way is applied on a conductive substrate by an immersion method and cured by heating in an oven at a temperature of 140 ° C. for 1 hour to increase the film thickness. A resin layer of 15 μm was formed.

Next, a solution prepared by dissolving the following components in a mixed solution of 400 parts of methanol / 200 parts of n-butanol was immersed and coated on the above-mentioned resin layer, and heated and dried in an oven at a temperature of 100 ° C. for 30 minutes. An intermediate layer having a film thickness of 0.60 μm was formed.
・ 10 parts of copolymerized nylon resin (trade name: Amiran CM8000, manufactured by Toray Industries, Inc.)
・ 30 parts of methoxymethylated 6 nylon resin (trade name: Tredin EF-30T, manufactured by Teikoku Kagaku Co., Ltd.)
In this way, an intermediate layer was formed on the resin layer, and the resin layer and the intermediate layer were combined to form an undercoat layer.

"Charge generation layer"
The following components were dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm, and then 700 parts of ethyl acetate was added to prepare a dispersion for a charge generation layer.
20 parts of hydroxygallium phthalocyanine (with strong peaks at 7.4 ° and 28.2 ° (Brag angle 2θ ± 0.2 °) in CuKα characteristic X-ray diffraction)
・ Calixarene compound 0.2 parts ・ Polyvinyl butyral 10 parts (Product name: Eslek BX-1, manufactured by Sekisui Chemical Co., Ltd.)
600 parts of cyclohexanone This was applied on the undercoat layer by a dip coating method and dried by heating in an oven at a temperature of 80 ° C. for 15 minutes to form a charge generation layer having a film thickness of 0.170 μm.

"Charge transport layer"
The following components were dissolved in a mixed solvent of 600 parts of monochlorobenzene and 200 parts of methylal to prepare a coating material for a charge transport layer. Using this, a charge transport layer was dipped and coated on the charge generation layer, and heated and dried in an oven at a temperature of 90 ° C. for 1 hour to form a charge transport layer having a film thickness of 20 μm.
・ 120 parts of hole transporting compound ・ 100 parts of polycarbonate resin (Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.)

"Protective layer"
30 parts of a hole transporting compound having a polymerizable functional group, 35 parts of 1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolar H, Nippon Zeon Co., Ltd.) A coating solution for a surface layer was prepared by dissolving it in 35 parts of a mixed solvent and then pressure-filtering it with a 0.5 μm membrane filter made of polytetrafluoroethylene (PTFE). After the coating liquid for the surface layer was immersed and coated on the charge transport layer, the object to be coated was held at 100 ° C. for 5 minutes to evaporate the solvent, and the formed coating film was air-dried.
Then, the object to be coated is irradiated with an electron beam (acceleration voltage 80 kV, dose 1.5 × 104 Gy) under a nitrogen atmosphere (oxygen concentration 10 ppm), and then an electrophotographic photosensitive member (electron beam coating) is irradiated under the same atmosphere. The curing treatment was performed for 90 seconds under the condition that the temperature of the irradiated body) was 120 ° C., and the coating film formed on the object to be coated was cured. Subsequently, the axial unevenness of the photoconductor film 310 of the obtained organic photoconductor 300 was measured. The film thickness was measured in the same manner as in Example 1.

Subsequently, in the axial direction, a region having a thick film thickness and a region having the thinnest film thickness were extracted. The thick region was 36.2 μm at the +150 mm position, and the thin region was 35.6 μm at the −150 mm position.

Next, the outer surface 311 of the organic photoconductor 300 was roughened as follows. In roughening, the polishing tape is sent to the rotating organic photoconductor 300 in the same direction as the rotation direction of the organic photoconductor 300, and the polishing tape is pressed against the outer surface 311 of the organic photoconductor 300 by a backup roller. It was carried out by. First, the entire surface of the organic photoconductor 300 was roughened under the following conditions.
・ Polishing sheet: Product name "GC (manufactured by Reflight Co., Ltd.)"
・ Abrasive grain count: 1500 or more and 4000 or less ・ Abrasive grain: SiC (average particle size: 1 μm or more and 15 μm or less)
And polishing sheet feed speed: 10mm / min or more 500mm / min or less-pressing pressure: 0.005N / ^{m 2} more than 15N / ^{m 2} or less

After that, an additional roughening treatment is performed under the above conditions only for the half on the +150 mm side from the center (0 mm) of the organic photoconductor 300 so as to include a thick region, and the surface roughness of the additional portion is increased. did. At the +150 mm position, the arithmetic mean roughness was 0.057 μm, and at the −150 mm position, the arithmetic mean roughness was 0.050 μm.

The organic photoconductor 300, which has been roughened, is subjected to iRC4570 manufactured by Canon Corporation (a charging member arranged in contact with the electrophotographic photoconductor by applying a voltage obtained by superimposing an AC voltage on a DC voltage to form an electrophotographic photosensitive member. The voltage applied to the charging roller was adjusted so that the average of one circumference of the dark surface potential at the center (0 mm) position of the electrophotographic photosensitive member 100 was −700 V.

After that, the durability test of 50,000 sheets was carried out in the same manner as in Example 1, and the image flow and the cleanability were evaluated. As a result, no image flow occurred and the cleanability was good.

100,200,300 Electrophotographic photosensitive member 101,201,301 Conductive substrate 110,210,310 Photoreceptor film 111,211,311 Outer surface 202 of photoconductor Lower charge injection blocking layer 203 Photoconductive layer 204 Surface layer 212, 312 Outer surface of substrate 302 Undercoat layer 303 Charge generation layer 304 Charge transport layer 305 Protective layer 400 Deposit forming device 401 Reaction vessel 402 Heating heater 403 Raw material gas introduction tube 404 Cone electrode 405 High frequency matching box 406 High frequency power supply 407 Auxiliary valve 408 Cradle 409 Vacuum gauge 410 Main valve 480 Accumulation device 490 Raw material gas supply device 500 Electrophotograph device 501 Charging device 502 Charging wire 503, 603 Image exposure light 504,604 Developing device 505,605 Transfer device 506,606 Transfer material 507,607 Cleaning device 508,608 Cleaning blade 509,609 Pre-exposure light 601 Charging roller

Claims (7)

An electrophotographic photosensitive member in which a photoconductor film containing at least a photoconducting layer and a surface layer is formed on a cylindrical conductive substrate.
When the surface potential of the electrophotographic photosensitive member when a constant charge is applied to the electrophotographic photosensitive member is used as the charging ability, the electrophotographic photosensitive member is said to be in the axial direction of the portion where the photoconductor film is formed. An electrophotographic feature in which the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in a region having a high chargeability is larger than the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in a region having a low chargeability. Photoreceptor. The electrophotographic photosensitive member of the portion where the photoconductor film is formed is divided into two regions in the axial direction, and the side having a high average value of the charging ability of the electrophotographic photosensitive member is designated as the first region. When the lower side is the second region, the average value of the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member in the first region is the outer surface of the electrophotographic photosensitive member in the second region. The electrophotographic photosensitive member according to claim 1, wherein the value is larger than the average value of the arithmetic mean roughness of the above. The average value of the chargeability in the first region is V1, the average value of the chargeability in the second region is V2, the average value of the arithmetic mean roughness in the first region is Ra1, and the second region. The electrophotographic photosensitive member according to claim 2, wherein the following formula (1) and the following formula (2) are satisfied when the average value of the arithmetic mean roughness in the region is Ra2.

The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member is 0.04 μm or more and 0.2 μm or less. In the axial direction of the electrophotographic photosensitive member in the portion where the photoconductor film is formed, the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member in a region where the film thickness of the photoconductor film is thick is determined by the photoconductor film. The electrophotographic photosensitive member according to claim 1, wherein the area having a thin film thickness is larger than the arithmetic mean roughness of the outer surface of the electrophotographic photosensitive member. A method for producing an electrophotographic photosensitive member in which a photoconductor film including at least a photoconducting layer and a surface layer is formed on a cylindrical conductive substrate.
When the surface potential of the electrophotographic photosensitive member when a constant charge is applied to the electrophotographic photosensitive member is used as the charging ability, the electrophotographic photosensitive member is said to be in the axial direction of the portion where the photoconductor film is formed. The roughening treatment is performed so that the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in the region having high chargeability is larger than the arithmetic average roughness of the outer surface of the electrophotographic photosensitive member in the region having low chargeability. A method for producing an electrophotographic photosensitive member, which comprises the above. The electrophotographic photosensitive member according to any one of claims 1 to 5.
An image forming apparatus comprising a charging member that is in contact with or close to the electrophotographic photosensitive member and that charges the electrophotographic photosensitive member by applying a voltage.

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